EMarketer predicts Instagram will earn $595 million in ad revenue this year and $2.81 billion by 2017.

How big? Big enough to pass Twitter and Google in mobile ad revenue in the next two years.

That’s according to a new forecast by industry analyst eMarketer. EMarketer predicts that the Faceboook-owned visual social network will bring in $595 million in global ad revenue this year. And by 2017, Instagram ad revenue will jump to $2.81 billion. That would be more than 10.6% of Facebook’s total 2017 ad revenue, according to eMarketer projections.

It would also surpass the net mobile revenue total for both Google and Twitter:

If the forecasts come true — or even approach the mark — it would be a significant windfall for Facebook. The company has been been very patient about monetizing Instagram, focusing first on brand awareness ads for large companies during 1 1/2 years of testing.

In June, Instagram announced that it will start selling ads — including direct response ads with links to “Shop Now,” “Install Now,” “Learn More” or “Sign Up” — to all interested businesses. It will also give advertisers the ability to use Facebook’s powerful targeting tools to place ads on Instagram.

Those moves have opened the floodgates, said Debra Aho Williamson, principal analyst for eMarketer.

“Now that Instagram is opening up, there is a lot of pent-up demand,” Williamson said. “The rollout of new features over the next several months means that by the end of 2015, Instagram will have a host of new ad products for advertisers large and small. In particular, Instagram advertisers will be able to use a full slate of Facebook targeting tools, including the popular Custom Audiences feature. That will be a key drawing card.”